The lab consists of about seventy people and it is structured into eight experimental teams. The research activity is mainly experimental in Physics and Optics : physical interactions between matter and waves, either in fundamental Physics (atomic and molecular physics, high-resolution spectroscopy...) or in more applied domains (organic light-emitting diodes, biomedical optics...), and often at the border of other area of science such as solid-state Physics, Chemistry, Biology, Nanosciences or Engineering. These studies range from isolated atoms to living media, including simple or complex molecules, molecular clusters and materials. Waves are either a coherent light (laser) that is used as a tool for obtaining information about the medium studied, or a matter wave to be studied for itself or also to be used as a tool in interaction with (nano)materials. The number of persons from LPL involved in the SEAM Labex represents about one half of the laboratory, with 15 permanent researchers (3 full-time CNRS researchers and 12 teacher-researchers), 2 engineers and 15 PhD students at the present time. All of them benefit from the support of the lab common services (mechanical shop, electronics, optics, IT, administration ; 10 persons).

Four teams are involved in the SEAM Labex :

1. Organic Photonics and Nanostructures (A. Boudrioua)

During the last years, this group realized a multilayer OLED, based on carbazolic materials, emitting pure blue light with excellent external quantum efficiency (3.3%). More recently, the group presented a new method to accurately control the color emission of the OLEDs, including white light. The present work is also orientated towards the conception of optically-pumped organic lasers and, ultimately, electrically-pumped organic laser that constitutes a major scientific challenge on which only very few French scientists are working. The team addresses this problem within complementary approaches (organic materials, electronics, lasers, nanotechnology and engineering). As a matter of fact, the use of micro-cavity is the main objective of the actual group work. It is suggested to utilize photonic crystal micro-cavities as well as vertical Bragg mirrors cavities in order to control photonic modes and therefore spontaneous and stimulated emissions, as an alternative to standard Distributed Feedback (DFB) or to planar DBR resonators. These research themes are 100% included within the scientific scope of the present Labex and interactions with other groups, either in physics, chemistry or engineering domains, are expected to strongly push forward these studies. For instance, these collaborations aim to efficiently use diamond and oxides materials elaborated at lspm for photonics crystals applications.

2. Hybrid Photosensitive Materials (A. Kanaev, L. Museur)

The aim of this joint LSPM-LPL team is to setup and characterize new hybrid materials based on titanium oxyde (TiO2) gels for photonic applications (3D information storage and electric switches form reversible laser micro-structuration). The LPL contribution is, firstly, to characterize the optical properties (linear and non-linear) and to realize the microstructuration patterns of these hybrid materials and, secondly, to analyze the dynamics and kinetics of the photo-induced charge carriers in correlation with key factors of elaboration processes.

3. Atomic spectroscopy at interfaces (D. Bloch)

This team is internationally recognized for studying atom-surface interactions at distances smaller than 100 nm, a distance much shorter than the current range of exploration of fundamental Casimir-type effects. These experimental skills now allow to use an atom as a quantum detector of the near-field "of a black-body radiator". The study of this near-field is indeed an emerging topics in nanophotonics, as a true black body is defined only in the far-field, while the near-field is sensitive to resonance properties associated with the spectral properties of the emitting material Also, the group now has opened a new research theme "Mesoscopic gas" (ANR contract), with confined atomic vapours, first in micro- and nano-cells, now with the 3D confinement offered by the interstitial regions of opals of nanospheres, and possibly with nanometric porous materials or hollow fibers. In these studies, the atomic mean free path is governed by the size of the interstitial regions, thus modifying the transient regime of the atomic optical response. Through a Dicke narrowing mechanism, mesoscopic gas can allow to combine sub-Doppler resolution and purely linear spectroscopy, a concept that may be extendable to molecular lines. Such a research should enable the development of compact photonic devices able to generate a precise reference frequency.

4. Atom Optics and Inteferometry (M. Ducloy, F. Perales)

This team is internationally well-known in the area of atomic waves and develops two lines of research that is of interest within the scope of this Labex. First, a coherent beam of metastable rare gas atoms is used for probing, via Van der Waals - Zeeman interactions at distances of few nanometers, various nanostructures like transmission gratings and magnetic (or not) reflection gratings. Although this distance range is important and implies specific phenomena (sticking, viscosity...), it is scarcely studied because of the experimental difficulties encountered at such short distances. On this topic, a collaboration is already running with two research teams of LSPM. Second, the group also built a new and original experimental setup for the realization of a metastable atom nano-beam that will be the equivalent of a pencil tip of nanometric size. This setup relies on a clever manipulation of magnetic potentials in order to transform the Gaussian spatial distribution of the atomic beam into a quasi-Lorentzian distribution (EU and USA patent). Theoretically, this should allow to focus the atomic beam down to few tens of nm. This original beam structure opens the way for atomic nano-lithography and could also constitute an atomic nano-probe. This new tool could be used, among others, for nano-components analysis.

The newly built Regional Platform for Nanotechnologies of Paris Nord C(PN)2 (A. Fischer) aims to create a technological pole of regional interest for both research and teaching in nanoscience, around photonics and associated nanomaterials themes, and in nanotechnology, around nanostructuration and nanofabrication techniques. It provides a fleet of shared technological equipments that will be widely open both to other neighboring academic research groups, especially within the Labex, and to local and regional companies for common research projects and technological transfers. It is focused on thin film nanostructuration of alternative materials - diamond, oxides, organics, hybrids - and their used for photonic applications.

The two clean room facilities included in the Labex (Paris Centre and Paris Nord) will share their complementary equipments. The various laser equipments at LPL will also benefit to all members of the Labex since some experiments need optical methods involving coherent light sources. LPL can offer a broad variety of lasers with wavelength from UV to IR range and from CW down to ns, ps and fs